What are Roman Numerals?
Roman Numerals are used to express numbers using capital letters. Here are the 7 letters used.
 I1
 V5
 X10
 L50
 C100
 D500
 M1000
How do Roman Numerals Work?
*Values greater than or equal to the number to there right are simply added on.
III=(1)+(1)+(1)

IX=(10)+(1)+(1)

Note: It is never necessary to place more than 3 identical capital letter next to one
another. When writing Roman Numerals, it is possible to write 4 as IIII.
However, because there are 4 identical capital letters, it is both easier and
more appropriate to write 4 as IV. Here is how it works. 
*Values smaller than the number to there right are subtracted from that (larger)
number.
IV=(5)(1)

IX=(10)(1)

IV includes the Roman numeral symbols of (1) and (5). However, because there is an I before
the V it is subtracted. 51=4. Likewise with IX, an I (1) is to the left of the X (10), therefore it is subtracted to equal 9.

Roman Numerals 110:
I 
II 
III 
IV 
VI 
VII 
VIII 
IX 
X 
More Information:
Last Update: 12/4/2004